Dear Mike, 

There may be many people who would like to become the Pope, but I don't think any of them ever will! There are others who want to be Bishops and never will either. So that part of the message might only be your imagination or just another of the idealistic, wonderful desires that capture our imagination when life is still all ahead of us. I wouldn't give it any special importance one way or the other, since anyway it is not something that depends on what you want.  

Where does that leave your desire to be a priest? It may or may not be the beginning of a sign of a vocation. I think it might help you to really think about what it is to be a priest. Read some of the lives of the saints (St John Vianney, St Maximilian Kolbe, St John Bosco, for example) and discover in them what it is to be a priest, the type of love for God it entails, the willingness to serve others and suffer for them.  

If what you read sets your heart on fire, makes you want the vocation more, you just may have one.